1. Field of the Invention
The present invention relates to a magnetic tape recording and playback apparatus in which modes of running the tape are switched in accordance with electric signal.
2. Description of the Background Art
Generally, a magnetic tape recording and playback apparatus comprises a tape driving system for running a cassette tape inserted thereto and a recording/playback system for recording/playing magnetic signals on the tape.
The tape driving system comprises, as basic elements, a motor serving as a power source, a pair of reel shafts engaging reels of the cassette tape and transmitting means for transmitting the rotation of the motor to the reel shafts.
The recording/playing system comprises a recording/playing head for recording magnetic signals on the tape or for reading magnetic signals recorded on the tape, and an erasing head for erasing the magnetic signals.
The basic operation modes of the magnetic tape recording and playback apparatus are a stopping mode, recording/playing mode, fast forwarding mode and rewinding mode. Various operation of the tape driving system and of the recording/playing system are combined to carry out prescribed operations in the respective operation modes. For example, in the recording/playing mode, the tape driving system rotates the motor so that a take-up reel of the cassette tape is rotated in a direction of taking up. At the same time, the recording/playing system moves forward a recording/playing head so that the recording/playing head is brought into contact with the surface of a tape running. The recording/playing head records or reads magnetic signals to and from the tape.
In the rewinding mode, the tape driving system rotates the motor to rotate a supply reel of the cassette tape. At the same time, the recording/playing system moves rearward the recording/playing head s that the recording/playing head is spaced away from the surface of the tape.
In this manner, various operation modes can be realized by controlling the operation of the tape driving system and the recording/playing system of the magnetic tape recording and playback apparatus. An example of a mechanism of the tape driving system is shown in U.S. Pat. No. 4,528,606. The tape driving mechanism shown in this example comprises a pair of rollers for transmitting rotation provided between a capstan shaft and a pair of reel shafts. The pair of rollers are rotatively attached to a rocking bracket. The rocking bracket is rotatively attached to the capstan shaft. A belt is wound around the pair of rollers and a pulley provided on the capstan shaft. The rotation of the motor is transmitted to the capstan shaft. The rocking bracket swings in a prescribed direction corresponding to the direction of rotation of the capstan shaft. By the swinging movement of the rocking bracket, either one of the pair of rollers is coupled to one of the reel shafts, so that the rotation is transmitted thereto.
An example of a mechanism of the recording/playing system is disclosed in U.S. Pat. No. Re. 32,007. The recording/playing head and the erasing head are mounted on a head base. The head base is movably attached on a chassis. The head base moves forward/rearward toward the surface of the inserted cassette tape. The head base is connected to a cam by means of a controlling lever. The cam is operated by a controlling motor. The controlling motor rotates in accordance with respective operation modes of the magnetic tape recording and playback apparatus. The cam moves forward/rearward the head base through the controlling lever corresponding to the operation of the controlling motor.
The mechanism of the tape driving system and the recording/playing system of a magnetic tape recording and playback apparatus is also shown in Japanese Patent Laying-Open Number 42659/1984. The tape driving system comprises a capstan shaft, a driving gear attached to the capstan shaft, a pair of planetary gears engaging with the driving gear and a rotary plate rotatably attached to the capstan shaft for rotatably supporting the planetary gear. The rotation of the motor is transmitted to the capstan shaft. The rotation of the capstan shaft swings the rotary plate in a prescribed direction. Consequently, one of the planetary gears engages with one of the reel shaft gears. The rotation of the motor is transmitted to the reel shaft gear through the capstan shaft, the driving gear and the planetary gear.
The recording/playing system comprises a head base on which the recording/playing head and the erasing head are mounted. The head base is movably attached on the chassis. The head base has its one end coupled to a turning lever connected to a plunger of a solenoid. The operation of the plunger of the solenoid moves forward/rearward the head base through the turning lever. That operation of the tape driving system and the movement of the head base are related with each other by means of an electric controlling system.
As described above, in the conventional magnetic tape recording and playback apparatuses, the mechanism of the tape driving system and that of the recording/playing system are independent from each other, and generally the prescribed operation modes are set by electric controlling means. Such structure is against the current trend of reducing the size of the magnetic recording and playback apparatuses, as it is large and the control system is complicated.